[XFS] implement generic xfs_btree_increment

From: Dave Chinner <dgc@sgi.com>

Because this is the first major generic btree routine this patch includes
some infrastrucure, first a few routines to deal with a btree block that
can be either in short or long form, second xfs_btree_read_buf_block,
which is the new central routine to read a btree block given a cursor, and
third the new xfs_btree_ptr_addr routine to calculate the address for a
given btree pointer record.

[hch: split out from bigger patch and minor adaptions]

SGI-PV: 985583

SGI-Modid: xfs-linux-melb:xfs-kern:32190a

Signed-off-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Lachlan McIlroy <lachlan@sgi.com>
Signed-off-by: Bill O'Donnell <billodo@sgi.com>
Signed-off-by: David Chinner <david@fromorbit.com>

1 files changed, 10 insertions, 0 deletions

diff --git a/fs/xfs/xfs_btree.h b/fs/xfs/xfs_btree.h
index 593f82b01b6f..f5a4b8ec4cdd 100644
--- a/fs/xfs/xfs_btree.h
+++ b/fs/xfs/xfs_btree.h
@@ -503,8 +503,18 @@ xfs_btree_setbuf(
 
 
 /*
+ * Common btree core entry points.
+ */
+int xfs_btree_increment(struct xfs_btree_cur *, int, int *);
+
+/*
  * Helpers.
  */
+static inline int xfs_btree_get_numrecs(struct xfs_btree_block *block)
+{
+        return be16_to_cpu(block->bb_numrecs);
+}
+
 static inline int xfs_btree_get_level(struct xfs_btree_block *block)
 {
         return be16_to_cpu(block->bb_level);